The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
The availability of unlicensed millimeter-wave (mm-wave) radio frequency (RF) bands is spurring the development of main stream applications that use mm-wave wireless technologies. For example, the Institute of Electrical and Electronics Engineers (IEEE) 802.11ad standard, also known as WiGig, promises up to approximately 7 Gigabits per second data rate over the 60 GHz frequency band for consumer applications such as wireless transmission of high-definition video.
In digital wireless communications systems, including those that operate in or near the 60 GHz frequency band, multipath propagation results in a form of signal distortion referred to as inter-symbol interference (ISI), where one transmitted symbol interferes with subsequently transmitted symbols. If unaddressed, ISI may lead to a high bit error rate in the receiver process and prevent the signal from being correctly decoded. To mitigate the negative effects of ISI, the receiving device typically employs an equalizer that reverses the distortion, thereby flattening the channel frequency response.
Frequency domain equalizers (FDEs) are a class of equalizers that operate in the frequency domain when correcting distortion. These equalizers are generally more effective at correcting distortion than equalizers that operate in the time domain. However, when operating on WiGig or other high frequency signals, FDEs typically consume more power than other classes of equalizers. In some cases, an FDE may not yield significant improvements over equalizers that operate in the time domain, especially where signal distortion is relatively low.
An alternative to an FDE is a decision feedback equalizer (DFE). A DFE uses feedback from previous symbol decisions to eliminate ISI on an incoming signal. A DFE generally requires less power than an FDE, but also has inferior performance in terms of distortion correction. The DFE's inferior performance may result in relatively high bit error rates and incorrect decoding when the received signal is highly distorted. Therefore, a DFE may not be suitable in some applications.